Abstract: The carrier suppression circuit of the present invention is utilized to minimize electrical imbalances within double-balanced mixers. The circuit operates upon a modulating signal, having at least two states so as to adjust the dwell time that the signal stays in a particular state to counteract the effects of electrical imbalance within the mixer. Minimization of the electrical imbalance provides a greater suppression of the carrier signal which, in turn, improves the quality of the signal both at the transmitter and at the receiver.

Abstract: A correlator error detector generates a first repeating digital pseudo noise code signal which is compared in a correlator to a second signal generated by the error detector with the second signal having the same pseudo noise code but with a noise signal intentionally added. The error detector measures the capability of the correlator to correlate the first signal with the second signal under varying noise conditions. Errors produced by the correlator are counted, and classified as being either missed correlation outputs or false correlation outputs.

Abstract: In the present invention a received DPSK signal is sampled at times corresponding to a peak signal to noise ratio and the sample of signal is passed to a circulating memory. A phase detector is connected to receive the DPSK signal and the sample of signal circulating in the memory to provide an output signal indicative of the phase relationships between the received DPSK signal and the circulating sample signal. A sampling means samples the output signal from the phase detector at the correct bit time, to provide a signal which is a function of the differential phase between adjacent bits of the received DPSK signal.